Venom listens and tries his best to figure out what might have transpired here. Ianto sounds so convinced that something did happen, possibly more than just shadows messing with him. Perhaps an illusion caused by residual magic. He wouldn't be surprised if some of the artifacts had spells cast on them in the past.

He glances over at the surrounding displays. "Hmmm... many of these items were probably used in at least one battle. You might have been seeing what they saw."